On conventional railroad trains, should a set of wheels come off the track and drop onto the ground, there is no way for the engineer to know that that event has occurred. The locomotive may drag the car whose wheels have come off the track several miles before the derailed wheels hit an obstruction, which ultimately causes a train wreck. Conventional trains have a pneumatic brake line mounted on the frame of each car, and air compressors in the locomotive pressurizing the air in the brake lines and carrying it to the brakes associated with each train car. The braking system is conventionally constructed so that should the pressure in the brake line be lost, the brakes will be automatically applied. In situations where there is a catastrophic release of air from the brake lines (as by the iron brake pipes rupturing or by the rubber connecting hoses coming loose), the brakes will go into emergency application.
According to the present invention, a method and apparatus are provided for facilitating the stopping of a train having a conventional pneumatic brake line should at least one wheel of the train go off the track. Utilizing the automatic stopping according to the present invention, it is possible to gradually bring the train to a halt before the train wrecks, or if the train ultimately does wreck, due to the reduced velocity caused by the stopping action according to the present invention, such a wreck should be much less severe.
According to a preferred method of the present invention, the stopping of a train when a wheel of one of its cars has left the track is accomplished by a method comprising the step of piercing a pneumatic brake line sufficiently to allow release of air from the brake line in response to the force created by a wheel of the train dropping down from the track on which it is riding. The piercing preferably takes place only in response to excessive vertical movement of the wheel, and effects sufficient leakage of air from the brake line to ultimately stop the train, but insufficient to cause catastrophic leakage of air from the brake line which would cause emergency stopping. The piercing is preferably accomplished by a cutting tool operatively connected to each wheel set of the train.
According to a preferred apparatus of the present invention, in combination with a railroad car having wheels and a pneumatic brake line, there is provided: means for facilitating stopping the train in response to at least one of the wheels going off the track, such means comprising means for piercing a pneumatic brake line to allow release of air from the brake line in response to at least one of the wheels going off the track. The piercing means preferably comprises a piercing mechanism mounted adjacent the brake line, and means interconnecting the piercing mechanism to at least one of the wheel sets of the railroad car, so that upon vertical movement of a wheel of the set a vertical distance corresponding to approximately half the height of the rail the piercing mechanism is activated, the activating force comprising the weight of the railroad car. The interconnecting means preferably comprises a cable or rod, having a loop formed at one end thereof, the loop loosely fitting around at least one axle of the wheel set. The piercing mechanism preferably comprises an arcuate cutting blade mounted for pivotal movement with respect to the brake line from a position wherein it does not pierce the brake line to a position wherein under the force of the railroad car weight the brake line is pierced, the interconnecting means comprising a lever operatively attached to the arcuate cutting blade for effecting pivotal movement thereof.
The apparatus according to the present invention is simple, easy to manufacture and install (it can be readily retrofitted on conventional trains without sending the cars to railroad shops), and should last the life of the railroad cars with which it is utilized. Additionally, it is not susceptible to false triggering since it responds only to vertical movement of the wheels off the tracks, not the horizontal movement normally encountered when the train rounds curves, etc.
It is the primary object of the present invention to provide a simple and inexpensive method and apparatus for automatically stopping a railroad train should at least one wheel of the train go off the track. This and other objectives of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.